The 2541 Redundant Processor Manager (RPM) provides an automatic backup solution for 2500 Series® PLCs. If the active PLC fails, the RPM will automatically switch the remote I/O to the standby PLC. Transfer to the standby PLC is bumpless. All remote I/O updates are mirrored to the standby PLC. In addition, up to 4096 words of user-defined critical data can be transferred from the active PLC to the standby PLC every scan. Other non-critical data can be transferred over several scans. The RPM can also switch up to two serially attached operator interface devices.

IMPORTANT NOTE: Due to extensive component obsolescence issues and insufficient demand to justify a re-engineering effort, this product has been matured.  For users needing PLC redundancy in the future, we have a solution planned based on our new Janus Programmable Automation Controller which uses two Janus PLCs and a Modbus relay that switches Remote I/O and Profibus networks from the primary PLC to the backup in case of a Processor failure.